title: Detection of venous air embolism in dogs by emission spectrometry.
abstract: Emission spectrometers provide alternative, relatively inexpensive methods for detecting the concentration of respiratory gas nitrogen. Mass spectrometers are accepted as reliable monitors of end-tidal nitrogen for detection of venous air embolisms. We evaluated an inexpensive emission spectrometer for detecting changes in nitrogen levels and compared it with a mass spectrometer for detecting increased end-tidal nitrogen levels in dogs with venous air embolisms. During in vitro gas flow studies (helium; oxygen; helium/oxygen mixtures; or 70% nitrous oxide/30% oxygen with 0, 1, 2, or 3% isoflurane), air boluses (0.01 to 5.0 ml) were injected into a gas flow circuit and outlet nitrogen levels were measured by a Collins 21232 emission spectrometer. Responses were greater after each bolus when helium rather than oxygen was the major diluent gas. During in vivo studies, 5 dogs were anesthetized, ventilated, denitrogenated, and given venous air embolisms (0.1, 0.5, and 1.0 ml.kg-1) during oxygen and then during Heliox (20% oxygen:80% helium) breathing. End-tidal nitrogen increased approximately two-fold after venous air embolisms given during Heliox as compared with oxygen ventilation. In all 0.1-ml.kg-1 venous air embolisms end-tidal nitrogen increased when the emission spectrometer was used, but venous air embolisms less than 1.0 ml.kg-1 were not consistently detected by mass spectrometry. Emission spectrometry can be used to detect increased end-tidal nitrogen levels indicative of venous air embolism and may be a more sensitive detector than mass spectrometry.
authors.affiliation: Department of Anesthesia, Pennsylvania State University, College of Medicine, University Hospital, Milton S. Hershey Medical Center, Hershey 17033.
authors.forename: G B
authors.initials: GB
authors.lastname: Russell
authors.forename: R B
authors.initials: RB
authors.lastname: Richard
authors.forename: M T
authors.initials: MT
authors.lastname: Snider
mesh_terms: D000818:Animals; D004285:Dogs; D004618:Embolism, Air / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D006371:Helium / Q000502:physiology; D007275:Injections, Intravenous / Q000009:adverse effects; D013058:Mass Spectrometry / Q000592:standards; D009584:Nitrogen / Q000502:physiology; D010100:Oxygen / Q000502:physiology; D013052:Spectrometry, X-Ray Emission / Q000592:standards*; D013990:Tidal Volume / Q000502:physiology; D014683:Vena Cava, Superior / Q000503:physiopathology*
chemical_list: D006371:Helium; D009584:Nitrogen; D010100:Oxygen